Separation of components (such as biomolecules, for instance DNA) of a fluidic sample becomes more and more important for medical applications, biochemistry, food chemistry, etc.
Conventional separation approaches such as gel electrophoresis or capillary electrophoresis become problematic when being applied to very small volumes of a biological sample.
Ken-ichi Inatomi et al. (2003) “Electrophoresis of DNA in micro-pillars fabricated in polydimethylsiloxane”, Microelectronic Engineering, Volume 70, Issue 1, pages 13 to 18 discloses the fabrication of a device containing micro-pillars for separation of DNA. It is made of polydimethylsiloxane (PDMS) and is manufactured by a replica molding method using a patterned silicon wafer as a mold. The device has a micro-channel in which 15 μm pillars are arranged in a hexagonal lattice with 1 μm spacing. Electrophoresis of DNA in the pillars showed that the average speed of DNA migration is dependent on its lengths.
However, a sufficient quality and reproducibility of the manufactured devices cannot be guaranteed due to the very nature of the fabrication process employed by Ken-ichi Inatomi et al. (2003). Furthermore, it would be very difficult to manufacture such devices on an industrial scale, as it will become clear in further sections below.